Malignant tumor is one of those diseases that seriously endanger human health. Currently, no effective treatment or prophylaxis is yet available. Thus, it is still the predominant task in the treatment of tumor to search for an effective preventive and/or therapeutic agent.
Vanillin compounds have aromatic odor, exhibit inhibition of bacterial growth and refreshing effect, and thus have been widely used as a food additive. Studies showed that vanillins, at a certain concentration, could also inhibit the activity of DNA repairing proteins DNA-PKcs and the invasion of cancer cells (Durant S and Karran P. Vanillins—a novel family of DNA-PK inhibitors. Nucleic Acids Research, 2003, 31(19): 5501-5512; Tsuda H, Uehara N, Iwahori Y, Asamoto M, Iigo M, Nagao M, Matsumoto K, Ito M and Hirono I. Chemopreventive effects of beta-carotene, alpha-tocopherol and five naturally occurring antioxidants on initiation of hepatocarcinogenesis by 2-amino-3-methylimidazo[4,5-f]quinoline in the rat. Jpn J. Cancer Res., 1994, 85: 1214-1219). Derivatives of vanillin include ethyl vanillin (molecular structure as shown in formula 1), 4-methoxyvanillin (molecular structure as shown in formula 2), isovanillin (molecular structure as shown in formula 3) and 2-bromo-isovanillin (molecular structure as shown in formula 4, also known as 6-bromo-isovanillin), and etc.

It is an effective approach in the development of new anticancer drugs to discover among various vanillin derivatives a compound having stronger activity of killing cancer cells and to identify the mechanism underlying the anticancer effect.